Glycine,C2H5O2N,is important for biological energy.The combustion reaction of glycine is described by the following thermochemical equation. 4C2H5O2N(s)+ 9O2(g)→ 8CO2(g)+ 10H2O(l)+ 2N2(g)ΔH°rxn = -3896 kJ/mol What is the standard enthalpy of formation of solid glycine?

A) -51.90 kJ/mol B) -527.5 kJ/mol C) -974.0 kJ/mol D) -1502 kJ/mol E) -2476 kJ/mol A) -51.90 kJ/mol B) -527.5 kJ/mol C) -974.0 kJ/mol D) -1502 kJ/mol E) -2476 kJ/mol

Sand is converted to pure silicon in a three-step process.The final step in this process is as follows. SiCl4(g)+ 2Mg(s)→ 2MgCl(s)+ Si(s)ΔH°rxn = -625.6 kJ/mol What is the enthalpy change if 25.0 mol of silicon tetrachloride is converted to elemental silicon?

A) -25.0 kJ B) -626 kJ C) -1.56 × l04 kJ D) -3.13 × 104 kJ E) -3.13 × 103 kJ A) -25.0 kJ B) -626 kJ C) -1.56 × l04 kJ D) -3.13 × 104 kJ E) -3.13 × 103 kJ

Using Hess's law,what is ΔH°rxn for the following reaction? WO3(s)+ 3H2(g)→ W(s)+ 3H2O(g) 2W(s)+ 3O2(g)→2WO3(s)ΔH°rxn = -1685.8 kJ/mol 2H2(g)+ O2(g)→ 2H2O(g)ΔH°rxn = -483.6 kJ/mol

A) 117.5 kJ/mol B) 235.0 kJ/mol C) 359.3 kJ/mol D) 1202.2 kJ/mol E) 2169.4 kJ/mol A) 117.5 kJ/mol B) 235.0 kJ/mol C) 359.3 kJ/mol D) 1202.2 kJ/mol E) 2169.4 kJ/mol

What is ΔH°rxn for the following reaction? C6H6(l)+ 15/2 O2(g)→ 6CO2(g)+ 3H2O(l) 6C(graphite)+ 3H2(g)→ C6H6(l) ΔH°rxn = +49.0 kJ/mol C(graphite)+ O2(g)→ CO2(g) ΔH°rxn = -393.5 kJ/mol H2(g)+ ½O2(g)→ H2O(l) ΔH°rxn = -285.8 kJ/mol

A) -630.3 kJ/mol B) -2597.8 kJ/mol C) -3169.4kJ/mol D) -3267.4 kJ/mol E) 630.3 kJ/mol A) -630.3 kJ/mol B) -2597.8 kJ/mol C) -3169.4kJ/mol D) -3267.4 kJ/mol E) 630.3 kJ/mol

What is ΔH°rxn for the reaction 2Al2O3(s)→ 4Al(s)+ 3O2(g)? ΔH°f(Al2O3(s))= -1670 kJ/mol

A) 3340 kJ/mol B) 1670 kJ/mol C) -3340 kJ/mol D) -1670 kJ/mol E) -835 kJ/mol A) 3340 kJ/mol B) 1670 kJ/mol C) -3340 kJ/mol D) -1670 kJ/mol E) -835 kJ/mol

Exam 5: Thermochemistry

Glycine,C₂H₅O₂N,is important for biological energy.The combustion reaction of glycine is described by the following thermochemical equation. 4C₂H₅O₂N(s)+ 9O₂(g)→ 8CO₂(g)+ 10H₂O(l)+ 2N₂(g)ΔH°_rxn = -3896 kJ/mol What is the standard enthalpy of formation of solid glycine?

(Multiple Choice)

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Question 41

In an endothermic reaction,in going from the reactants to the products at the same temperature,the value of q is negative.

(True/False)

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Question 42

A system that does no work but which receives heat from the surroundings has

(Multiple Choice)

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Question 43

Sand is converted to pure silicon in a three-step process.The final step in this process is as follows. SiCl₄(g)+ 2Mg(s)→ 2MgCl(s)+ Si(s)ΔH°_rxn = -625.6 kJ/mol What is the enthalpy change if 25.0 mol of silicon tetrachloride is converted to elemental silicon?

(Multiple Choice)

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Question 44

Using Hess's law,what is ΔH°_rxn for the following reaction? WO₃(s)+ 3H₂(g)→ W(s)+ 3H₂O(g) 2W(s)+ 3O₂(g)→2WO₃(s)ΔH°_rxn = -1685.8 kJ/mol 2H₂(g)+ O₂(g)→ 2H₂O(g)ΔH°_rxn = -483.6 kJ/mol

(Multiple Choice)

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Question 45

A system initially has an internal energy U of 504 J.It undergoes a process during which it releases 111 J of heat energy to the surroundings,and does work of 222 J.What is the final energy of the system,in J?

(Multiple Choice)

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Question 46

If,as a pioneer,you wished to warm your room by taking an object heated on top of a pot-bellied stove to it,which of the following 15-pound objects,each heated to 100°C,would be the best choice? The specific heat capacity (in J/g·°C)for each substance is given in parentheses.Iron (0.450),copper (0.387),granite (0.79),gold (0.129),water (4.184).

(Multiple Choice)

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Question 47

What is ΔH°_rxn for the following reaction? C₆H₆(l)+ 15/2 O₂(g)→ 6CO₂(g)+ 3H₂O(l) 6C(graphite)+ 3H₂(g)→ C₆H₆(l) ΔH°_rxn = +49.0 kJ/mol C(graphite)+ O₂(g)→ CO₂(g) ΔH°_rxn = -393.5 kJ/mol H₂(g)+ ½O₂(g)→ H₂O(l) ΔH°_rxn = -285.8 kJ/mol

(Multiple Choice)

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Question 48

The sign of q when heat is absorbed by the system is ___________.

(Short Answer)

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Question 49

Ethylene glycol,used as a coolant in automotive engines,has a specific heat capacity of 2.42 J/g°C.Calculate q when 3.65 kg of ethylene glycol is cooled from 132°C to 85°C.

(Multiple Choice)

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Question 50

An exothermic reaction causes the surroundings to

(Multiple Choice)

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Question 51

What is ΔH°_rxn for the reaction 2Al₂O₃(s)→ 4Al(s)+ 3O₂(g)? ΔH°_f(Al₂O₃(s))= -1670 kJ/mol

(Multiple Choice)

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Question 52

Which of the following processes always results in an increase in the energy of a system?

(Multiple Choice)

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Question 53

A(n)_ is a process where heat is released to the surroundings.

(Short Answer)

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Question 54

Which equation has a ΔH_rxn that is not equal to ΔH^o_f of the product? rev: 04_28_2015_QC_CS-14747

(Multiple Choice)

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Question 55

Cold packs,whose temperatures are lowered when ammonium nitrate dissolves in water,are carried by athletic trainers when transporting ice is not possible.Which of the following is true of this reaction?

(Multiple Choice)

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Question 56

Which relationship is always correct?

(Multiple Choice)

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Question 57

Solid sodium peroxide (Na₂O₂)reacts with liquid water yielding aqueous sodium hydroxide and oxygen gas.How much heat is released if 327.2 g of oxygen gas is produced from the reaction of sodium peroxide and water under standard-state conditions? Substance ΔH°_f(kJ/mol) Na₂O₂ (s)-510.9 NaOH(aq)-469.6 H₂O(l)-285.8

(Multiple Choice)

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Question 58

The highly exothermic thermite reaction,in which aluminum reduces iron(III)oxide to elemental iron,has been used by railroad repair crews to weld rails together. 2Al(s)+ Fe₂O₃(s)→ 2Fe(s)+ Al₂O₃(s)ΔH°_rxn = -847.6 kJ/mol What mass of iron is formed if 725 kJ of heat are released?

(Multiple Choice)

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Question 59

The work done on the surroundings by the expansion of a gas is w = -PΔV.

(True/False)

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Question 60

Showing 41 - 60 of 134

Exam 5: Thermochemistry

Glycine,C2H5O2N,is important for biological energy.The combustion reaction of glycine is described by the following thermochemical equation. 4C2H5O2N(s)+ 9O2(g)→ 8CO2(g)+ 10H2O(l)+ 2N2(g)ΔH°rxn = -3896 kJ/mol What is the standard enthalpy of formation of solid glycine?

In an endothermic reaction,in going from the reactants to the products at the same temperature,the value of q is negative.

A system that does no work but which receives heat from the surroundings has

Sand is converted to pure silicon in a three-step process.The final step in this process is as follows. SiCl4(g)+ 2Mg(s)→ 2MgCl(s)+ Si(s)ΔH°rxn = -625.6 kJ/mol What is the enthalpy change if 25.0 mol of silicon tetrachloride is converted to elemental silicon?

Using Hess's law,what is ΔH°rxn for the following reaction? WO3(s)+ 3H2(g)→ W(s)+ 3H2O(g) 2W(s)+ 3O2(g)→2WO3(s)ΔH°rxn = -1685.8 kJ/mol 2H2(g)+ O2(g)→ 2H2O(g)ΔH°rxn = -483.6 kJ/mol

A system initially has an internal energy U of 504 J.It undergoes a process during which it releases 111 J of heat energy to the surroundings,and does work of 222 J.What is the final energy of the system,in J?

What is ΔH°rxn for the following reaction? C6H6(l)+ 15/2 O2(g)→ 6CO2(g)+ 3H2O(l) 6C(graphite)+ 3H2(g)→ C6H6(l) ΔH°rxn = +49.0 kJ/mol C(graphite)+ O2(g)→ CO2(g) ΔH°rxn = -393.5 kJ/mol H2(g)+ ½O2(g)→ H2O(l) ΔH°rxn = -285.8 kJ/mol

The sign of q when heat is absorbed by the system is ___________.

Ethylene glycol,used as a coolant in automotive engines,has a specific heat capacity of 2.42 J/g°C.Calculate q when 3.65 kg of ethylene glycol is cooled from 132°C to 85°C.

An exothermic reaction causes the surroundings to

What is ΔH°rxn for the reaction 2Al2O3(s)→ 4Al(s)+ 3O2(g)? ΔH°f(Al2O3(s))= -1670 kJ/mol

Which of the following processes always results in an increase in the energy of a system?

A(n)___________ __________ is a process where heat is released to the surroundings.

Which equation has a ΔHrxn that is not equal to ΔHof of the product? rev: 04_28_2015_QC_CS-14747

Cold packs,whose temperatures are lowered when ammonium nitrate dissolves in water,are carried by athletic trainers when transporting ice is not possible.Which of the following is true of this reaction?

Which relationship is always correct?

The highly exothermic thermite reaction,in which aluminum reduces iron(III)oxide to elemental iron,has been used by railroad repair crews to weld rails together. 2Al(s)+ Fe2O3(s)→ 2Fe(s)+ Al2O3(s)ΔH°rxn = -847.6 kJ/mol What mass of iron is formed if 725 kJ of heat are released?

The work done on the surroundings by the expansion of a gas is w = -PΔV.

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Glycine,C₂H₅O₂N,is important for biological energy.The combustion reaction of glycine is described by the following thermochemical equation. 4C₂H₅O₂N(s)+ 9O₂(g)→ 8CO₂(g)+ 10H₂O(l)+ 2N₂(g)ΔH°_rxn = -3896 kJ/mol What is the standard enthalpy of formation of solid glycine?

Sand is converted to pure silicon in a three-step process.The final step in this process is as follows. SiCl₄(g)+ 2Mg(s)→ 2MgCl(s)+ Si(s)ΔH°_rxn = -625.6 kJ/mol What is the enthalpy change if 25.0 mol of silicon tetrachloride is converted to elemental silicon?

Using Hess's law,what is ΔH°_rxn for the following reaction? WO₃(s)+ 3H₂(g)→ W(s)+ 3H₂O(g) 2W(s)+ 3O₂(g)→2WO₃(s)ΔH°_rxn = -1685.8 kJ/mol 2H₂(g)+ O₂(g)→ 2H₂O(g)ΔH°_rxn = -483.6 kJ/mol

What is ΔH°_rxn for the following reaction? C₆H₆(l)+ 15/2 O₂(g)→ 6CO₂(g)+ 3H₂O(l) 6C(graphite)+ 3H₂(g)→ C₆H₆(l) ΔH°_rxn = +49.0 kJ/mol C(graphite)+ O₂(g)→ CO₂(g) ΔH°_rxn = -393.5 kJ/mol H₂(g)+ ½O₂(g)→ H₂O(l) ΔH°_rxn = -285.8 kJ/mol

What is ΔH°_rxn for the reaction 2Al₂O₃(s)→ 4Al(s)+ 3O₂(g)? ΔH°_f(Al₂O₃(s))= -1670 kJ/mol

A(n)_ is a process where heat is released to the surroundings.

Which equation has a ΔH_rxn that is not equal to ΔH^o_f of the product? rev: 04_28_2015_QC_CS-14747

The highly exothermic thermite reaction,in which aluminum reduces iron(III)oxide to elemental iron,has been used by railroad repair crews to weld rails together. 2Al(s)+ Fe₂O₃(s)→ 2Fe(s)+ Al₂O₃(s)ΔH°_rxn = -847.6 kJ/mol What mass of iron is formed if 725 kJ of heat are released?